请问python身份运算符如何使用

Question

请问python身份运算符如何使用

Answer 1

Python身份运算符身份运算符用于比较两个对象的存储单元

以下实例演示了Python所有身份运算符的操作：

#!/usr/bin/pythona = 20b = 20if ( a is b ):print "Line 1 - a and b have same identity"else:print "Line 1 - a and b do not have same identity"if ( id(a) == id(b) ):print "Line 2 - a and b have same identity"else:print "Line 2 - a and b do not have same identity"b = 30if ( a is b ):print "Line 3 - a and b have same identity"else:print "Line 3 - a and b do not have same identity"if ( a is not b ):print "Line 4 - a and b do not have same identity"else:print "Line 4 - a and b have same identity"

以上实例输出结果：

Line 1 - a and b have same identityLine 2 - a and b have same identityLine 3 - a and b do not have same identityLine 4 - a and b do not have same identity

Answer 2

1 2 3 4 5

>>> 10 << 1 20 >>> 10 >> 1 5 >>>

<<是按位左移，>>是按位右移。移一位的时候，等同于*2, /2.

 

Answer 3

左移运算是将一个二进制位的操作数按指定移动的位数向左移位，移出位被丢弃，右边的空位一律补0。

右移运算是将一个二进制位的操作数按指定移动的位数向右移动，移出位被丢弃，左边移出的空位或者一律补0，或者补符号位，这由不同的机器而定。

用起来是这样的

1 2 3 4 5 6 7 8 9 10 11 12

>>> 3<<1 6 >>> 1<<1 2 >>> 2<<1 4 >>> 2<<1 4 >>> 4<<1 8 >>> 5<<1 10